Preparation of alkyl phenanthrenes

ABSTRACT

LIGHT CYCLE OIL RESULTING FROM THE MANUFACTURE OF PETROLEUM PITCH IS CONTACTED WITH A CATALYST IN THE PRESENCE OF HYDROGEN GAS AND FRACTIONATED INTO A CUT CONTAINING ALKYL PHENANTHRENES.

United States Patent O 3,737,472 PREPARATION OF ALKYL PHENANTHRENES William S. Green, Columbus, Ohio, and John W. Newman, Ashland, Ky., assignors to Ashland Oil, Inc., Houston, Tex. No Drawing. FiledMay 6, 1971, Ser. No. 140,950 Int. Cl. C07c 15/30 US. Cl. 260-668 F Claims ABSTRACT OF THE DISCLOSURE Light cycle oil resulting from the manufacture of petroleum pitch is contacted with a catalyst in the presence of hydrogen gas and fractionated into a cut containing alkyl phenanthrenes.

FIELD OF THE INVENTION This invention relates to the preparation of alkyl phenanthrenes. More specifically, it relates to the preparation of methyl phenanthrenes from aromatic feed stocks derived from petroleum refining streams.

BACKGROUND OF THE INVENTION The alkyl phenanthrenes have the structural formula of the following configuration wherein an alkyl group is attached at one or more of the positions 1, 2, 3, 4, 9 and/ or 10 as indicated:

The methyl phenanthrenes in which a methyl radical is attached at one or more of the above indicated positions have melting points ranging from 50 to 191 C. The alkyl phenanthrenes, particularly the methyl phenanthrenes offer a number of uses such as furnishing the source material for the manufacture of plasticizers and as a heat transfer fluid. The alkyl groups are capable of being oxidized to form acid moieties which can be esterified to form the plasticizer agent.

We have now discovered that methyl phenanthrene can be derived from certain feedstocks resulting indirectly from the catalytic cracking of petroleum hydrocarbons and manufacture of petroleum pitch. Catalytic cracking is today a process of major importance in petroleum refining particularly in the production of gasoline. The feedstock for catalytic cracking is primarily distilled gas oil charge stock resulting from topping crude oil.

Catalytic cracking of the gas oil charge stock produces gasoline fractions, gas products, and heavier liquid bottom fractions known in the industry as light cycle and heavy cycle ends, and a heavy slurry oil containing suspended catalyst fines. Ordinarily these heavy and light cycle oils are recycled to the cracking unit and cracked further. The slurry oil is treated by decantation to remove the fines and recycled as decant oil to the cracking process.

In some refining systems, however, the treated slurry oil or decant oil is used as a feedstock for making petroleum pitch. The decant oil is thermally cracked under heat and vacuum at temperatures between about 850 and 1050" F. The products from this process are the desired petroleum pitch, gas oil products (hereinafter referred to as cycle oil), hydrocarbon gas, and gasoline. Ordinarily at least a portion of the gas oil products is recycled to the cracking step for further conversion to pitch. An example of a process for making petroleum pitch is described in US. Pat. 3,140,248.

3,737,472 Patented June 5, 1973 BRIEF DESCRIPTION OF THE INVENTION We have now discovered that by contacting the cycle oil efiluent stream from the petroleum pitch making process with a suitable catalyst in the presence of a hydrogen stream and subsequent fractionation, phenanthrenes hearing one or more substituted methyl groups are recovered.

DETAILED DESCRIPTION OF THE INVENTION The cycle oil effluent from the petroleum pitch making process ordinarily has a density of between about 15 API and 5 API. A typical boiling point analysis of this stream is shown in Table I.

Ideally the cycle oil stream, such as that typified above, is passed through a catalyst bed at a temperature of about 700 F. to 1200" F. and at a pressure of about 700 to about 1000 p.s.i. while in contact with hydrogen gas. The efiluent stream is then fractionated to yield a pure mixture of methyl phenanthrenes.

Catalysts that can be used for our process are nickelmolybdena, cobalt-molybdena or chromia on an alumina base. The preferred catalyst is nickel-molybdena (for example HDS-3 manufactured by the American Cyanamid Company). The catalyst may be in one or more beds and may be the same or different in the several zones of a single bed.

Typical compositions and physical properties of the cobalt-molybdena and nickel-molybdena catalysts are:

' Composition: Wt. percent C00 or NiO 3.2 M00 15.1 Na O 0.02 Fe 0.04 80.; -5 0.3 SiO 0.1 Loss on ignition 1.4

Physical properties Co-MO3 NiO-MO Apparent bulk density, lbs/It. 33 40 Compacted bulk density- 36 43 Pore volume, cc.lg 0. 7 0.6 Surface area, m.z/g 270 180 The temperatures employed in the catalyst bed or beds can be in the range of about 700 to 1200" F. and preferably in the range of about 800 to 1100 F. and more preferably in the range of about 900 to about 1000 F. The partial pressure of hydrogen can be as low as 400 p.s.i. but the preferred range is about 650 p.s.i. to 950 Analysis of liquid:

p.s.i. A space velocity of about 0.5 to about 2.5 volumes of liquid per volume of catalyst can be used. Preferred space velocities are about 0.8 to about 1.5. The rate of gas injection to the catalyst bed can be in the range of about 400 to 20,000 s.c.f. per barrel of cycle oil passed into the catalyst bed, the upper limit being dictated by economic considerations. The preferred range of gas injection is about 9000 to 14,000 s.c.f. per barrel of cycle oil injected. The subsequent step of fractionation is conducted at those temperatures and pressures which will result in a sharp cut of the materials boiling in the temperature range of methyl phenanthrene and other alkyl phenanthrenes.

EXAMPLE 1 In the laboratory, a feed stream comprising cycle oil efiiuent from the pitch making process described previously and of the composition near that shown in Table I and having a specific gravity of 1.150 was passed through a bed of catalyst comprising nickel-molybdenum on alumina.

Processing conditions were as follows:

Weight hourly space velocity 0.9 Hydrogen rate, s.c.f./bbl 11,525 Hydrogen partial pressure, p.s.i.g 650 Total pressure in bed, p.s.i.g 1,000 Average bed temperature, F. 978 Yield of liquid, percent of feedstock recovered 90 M01 percent Material of molecular weight less than naphthalene 4.5 Naphthalene 1.9 Material of molecular weight from naphthalene to phenanthrene and anthracene 18.0 Phenanthrene and anthracene 15.8 Methyl phenanthrene 21.1 Material of molecular Weight greater than methyl phenanthrene 38.7

What is claimed is:

1. A method for producing alkyl phenanthrenes comprising:

(a) passing a light cycle oil derived from the production of petroleum pitch over a catalyst selected from the group consisting of nickel-molybdena, cobaltmolybdena, and chromia supported on an alumina base while contacting said light cycle oil with hydrogen gas; and

(b) fractionating the resulting liquid product into at least one fraction containing alkyl phenanthrenes.

p 2, The method of claim 1 wherein said step of passing (a) is conducted at a pressure of about 700 to about 1000 p.s.i.,

3. The method of claim 1 wherein the partial pressure of hydrogen gas is between about 400 to about 950 p.s.i. 4. The method of claim 1 wherein the hydrogen gas is injected in a ratio of about 4000 to about 20,000 s.c,f.

per barrel of light cycle oil injected.

5. The method of claim 1 wherein the temperature in step (a) is between about 700 and 1200" F.

6. The method of claim 1 wherein said catalyst is nickel-molybdena supported on an alumina base.

7. The method of claim 1 wherein the space velocity of said light cycle oil is between about 0.5 and about 2.5.

8. The method of claim 1 wherein the alkyl phenanthrene recovered is a mixture of isomers of methyl phenanthrene.

9. The method of claim 1 wherein said light cycle oil has an API gravity of about 15 to about 5.

10. A method for producing methyl phenanthrene,

comprising:

(a) passing a liquid petroleum hydrocarbon derived from the production of petroleum pitch over a nickel-molybdena on alumina catalyst at a pressure of about 700 to about 1000 p.s.i., a temperature of about 800 to about 1100 F., and a space velocity of about 0.8 to about 1.5;

(b) simultaneously contacting said liquid petroleum hydrocarbon withhydrogen gas at a partial pressure of about 650 to about 950 p.s.i., said gas being contacted with said liquid petroleum hydrocarbon at a ratio of about 9800 to about 14,000 s.c.f. of hydrogen gas per barrel of said liquid petroleumhydrocarbon; and

(c) fractionating the resulting liquid product into a fraction containing methyl phenanthrene.

References Cited UNITED STATES PATENTS 2,958,643 11/1960 Friedman 260-668 D 3,001,929" 9/1961 Moy et al 208136 3,001,930 9/1961 White et al. 208136 3,179,602 4/1965 Gremillion 208 136 CURTIS R. DAVIS, Primary Examiner US. Cl. X.R. 260668 D 

